Polyamides containing adjacent heterocycle linkages



3,376,269 Patented Apr. 2, 1968 United States Patent ice y from the description of the invention which follows here- 3,376,269 POLYAMIDES CONTAINING ADJACENT HETEROCYCLE LINKAGES Jack Preston, Raleigh, N.C., assignor to Monsanto Company, a corporation of Delaware inafter.

V This invention is concerned with the provision and preparation of symmetrical amide-heterocycle polymers having the formula No Drawing. Filed Feb. 26, 1964, Ser. No. 347,385

11 Claims. (Cl. 260-78) E I HN-Y'-NH o-Yo- This invention relates to new high temperature resist- L J ant linear condensation polymers. More particularly, the invention relates to polymers with regularly recurring structural units containing amide linkages and bis-heterocyclic linkages.

Synthetic linear condensation polymers such as polyamides in the form of fibers, filaments, films and other wherein Y and Y are selected from Ar and Ar-X--X-Ar Where Ar is an aromatic divalent radical which may have a single, multiple or fused structure, and X represents a divalent 5 or 6 ring member heterocyclic linkage which contains from one to three hetero elements shaped articles have found wide application in textile and Such as O and In the general formula other industrial end uses requiring high tensile strength, Y and Y may be the same or difierent provided that abrasion resistance, and resistance to thermal and other t e is at least one Ar-X-X-Ar linkage in each repeat degradative conditions. Subsequent searching for polyg lmit- All occurrences of X in tha P l/ repeatmers of improved thermal resistance has produced variing unit must be the same. In each Ar-X-X-Ar linkage Ous heterocycle polymers such a olyo dia l poly- 0 the two heterocyclic radicals are joined to each other by benzirnidazoles, and polyimides. Typical of such polya single common carbon to carbon valence bond.

mers are those in US. Patents 2,895,948, 2,904,537 and The use of the term symmetrical herein is intended 3,044,994. Such heterocycle polymers have certain charto relate to a characteristic of the polymers of this inven-v acteristics, including heat resistance and resistance to tion which may be described by the fact that there is at acids and other degradative conditions, which are supeleast one point in each repeating unit of the polymers through which a plane of symmetry can be drawn. For

rior to those of polyamides in general. Wholly aromatic example, repeating units may be shown as follows:

polyamides such as those of US. 3,006,899 and 3,049,518

plane of symmetry mirror image half mirror image half and I E n I O -HN 0 0-5-0 C -NH-C Q} A u u u u mI N-N NN plane of symmetry mirror image half mirror image half have also been found to be highly resistant to high temwherein a plane of symmetry as indicated by the dotted peratures. This invention presents polymers which comline shows that the repeating unit consists of two halves bine the desirable qualities and characteristics of both which are mirror images of each other.

aromatic polyamides and heterocycle polymers. The heterocyclic linkages are exemplified by Accordingly, it is an object of this invention to pro- N N vide new compositions of matter and a process for their Preparafim- I I n n Another object of this invention is the provision of novel amideheterocycle polymers which are characterized by the fact that they have amide and two adjacent heterocyclic linkages in each repeating unit which appear in a perfectly regular sequence along the polymer H H H H y H H H chain, each amide and each pair of adjacent heterocy- N N N N N clic linkages being separated by an aromatic radical, the polymers further being characterized by the fact that there is at least one point in each repeating unit of the J I I Sizing-er through which a plane of symmetry can be l H |l I ll ll It is a further object to provide polymers which possess unusual thermal stability.

An additional object of the invention is the provision of fibers, filaments, films and other shaped articles prepared from the amide bis-heterocycle polymers of this invention.

Other objects and advantages will become apparent C and H l I where R=H, lower alkyl or phenyl.

Suitable aromatic linkages include W 10 where R is O-, --S, ---SO;;- and the like.

As examples of the polymers of this invention the following may be cited:

The polymers of this invention may be prepared by O 0 reacting together two monomers, each containing functional groups which react with the functional groups of Q' ff? the other to produce a polymer containing amide and two I i N or four heterocyclic linkages in each repeating unit which appear in a perfectly regular sequence along the polymer 0 0 chain. Thus, the polymers may be prepared via the reac- NH 2 C C'C C NH3 tron of an aromatic 'dlaCld chloride with an aromatic di- H 1% IE amine containing two heterocyclic linkages separated by an aromatic linkage or from the reaction of an aromatic diacid chloride containing two heterocyclic linkages separated by an aromatic linkage with an aromatic diamine.

An alternate route to the polymers of this invention emmeihods of Pfcpafafion 0f e am es f this ploys the reaction of a monomer containing preformed fill/6119011 In general are described y Karfef et amide linkages and functional groups which, when reacted 35 Helv- 820 and Stoll, Pfaktische with the functional groups of a second monomer, produce -9 139 HOD-Conveniently, it involves the P P' h t 1i 1i k Th polymen'zation of h reactants aration of dinitro intermediate which is then reduced to is a condensation reaction which may be conveniently conthe diam-i116 Compound containing heterocyclic linkages ducted by interfacial or solution polymerization methods, The dinitro intermediate y be P p y any of by heating of stoichiometric amounts of reactautsand the 40 v r l w known methods A 1, i l i k g like. may be formed from a hydrazide linkage which may be The following equations are exemplary of how the polyformed in solution or via a Schotten-Baumann reaction. mers of the invention can be prepared: The Schotten-Baumann or interfacial type reaction in- Of the several routes to the preparation of the polymers volves the use of a nitroaromatic acid chloride either alone of this invention, the polymerization of an aromatic dior in a suitable solvent which will dissolve the acid chloamine containing two adjacent heterocyclic linkages, i.e., ride and which will at the same time not adversely alfect a bis-heterocyclic linkage, is typical. the other component which is dissolved or, dispersed in As examples f the di mi w i h m y be used in h Water. Suitable solvents include chloroform, tetrahydropractice of this invention, the following are typical and furan, benzene, benzonitrile, acetophenone, acetontrile, illustrative. dimethylacetamide, and other solventstetrahydrofuran being preferred. The reaction mixture is then stirred NH NH rapidly until the reaction is completed and the dinitro g 2 compound is filtered from the reaction mixture. The

Hs S choice of intermediate reactants will, of course, depend upon the type of heterocyclic linkage desired. For example, the reaction of m-nitrobenzoyl chloride plus oxalic dihydrazide in a basic reaction media will produce a nitro-m-benzoylhydrazide intermediate which may then be converted by a dehydrating agent, such as phosphorous pentoxide, to a dinitro intermediate compound containing a bis-1,3,4-oxadiazole linkage. The hydrazide intermediate may also be produced in a solvent, such as dirnethylacetamide. The dintro compound containing the bis-oxadiazole linkage may then be reduced to the diamino compound.

It is also possible to prepare the dinitro hetero-containing intermediate in a one-step synthesis. Other bis-heterocyclic linkages may be preformed readily in the compositions of this invention. Such heterocyclic linkages include: bis 1,3,4 thiodiazole, bis-3,5-4-N-phenyl-l,2,4- triazole, bis-pyrazole, bis-oximidazole, etc.

The reduction of the dinitro intermediate to the diamine may be effected by use of catalytic reducing methods such as those involving the use of a palladium on charcoal catalyst typically employing 5 percent palladium on charcoal, a Parr hydrogenation unit or other unit. The reduction may also employ Raney nickel, cobalt and other similar heavy metal catalysts, these catalyst systems usually being effected in an alcohol or in solution in dimethylformamide or similar compounds. Reduction may also be accomplished using chemical reduction methods, such as stannous chloride and hydrochloric acid, iron and sulfuric acid, polysuliide solutions and the like.

Suitable dicarboxylic acids or diacid derivatives which may be used in the practice of the invention include all diacid compounds where the carbonyl radicals are joined by aromatic or bis-heterocyclic-aromatic linkages, for example, aromatic diacid halides, such as isophthaloyl halide and substituted isophthaloyl chlorides such as alkyl, aryl, alkoxy, nitro and other similar isophthaloyl chlorides and isophthaloyl bromides. Examples of such compounds include 4,6-dimethyl-5-propyl isophthaloyl chloride, 2,5- dimethyl isophthaloyl chloride, 2,5-dimethoxy isophthaloyl chloride, 4,6-dimethoxy isophthaloyl chloride, 2,5- diethoxy isophthaloyl chloride, S-propoxy isophthaloyl chloride, 5-phenyl isophthaloyl chloride, 2-methyl-5- phenyl isophthaloyl chloride, 2,5-dinitro isophthaloyl chloride, S-nitro isophthaloyl chloride and the like. Terephthaloyl chloride or terephthaloyl bromide may also be used and may be substituted in the manner described above for isophthaloyl chloride. Examples of terephthaloyl chlorides include 2,6-dimethyl terephthaloyl chloride, tetramethyl terepththaloyl chloride, Z-methoxy terephthaloyl chloride, 2-nitro terephthaloyl chloride and the like.

These diacid monomers may be prepared by any of the will known prior art methods used to prepare aromatic diacid compounds. For example, oxidation of xylenes.

The polymers of the invention may be obtained by any of the well known condensation polymerization techniques such as solid state, melt, interfacial or solution polymerization techniques.

The solution polymerization method generally involves dissolving the diamine in a suitable solvent which is inert to the polymerization reaction. Among such solvents there may be mentioned dimethylacetarnide, l-methyl-Z- pyrrolidone, 1,5-dimethyl-2-pyrrolidone and the like. These solvents are rendered more effective in many instances by mixing them with a small amount, up to percent, of an alkali or alkaline earth salt such as lithium chloride, lithium bromide, magnesium bromide, magnesium chloride, beryllium chloride, or calcium chloride.

The preferred solvent for solution polymerization is dimethylacetamide or dimethylacetamide containing a small amount of dissolved lithium chloride. The diamine solution may be cooled to between and C. and the dicarbonyl monomer may be added either as a solid or in a solution of one of the aforementioned solvents. The mixceptor is then added and the mixture is then stirred rapidly. During this rapid stirring a solution of the dicarbonyl monomer in an inert organic solvent is added, the mixture is stirred until polymerization is complete, the polymer is then isolated by filtration and is washed and dried. The dicarbonyl monomer solvent may be any convenient solvent such as a cyclic non-aromatic oxygenated organic solvent such as a cyclic tetramethylene sulfone, 2,4-dimethyl cyclic tetramethylene sulfone, tetrahydrofuran, propylene oxide and cyclohexanone. Other suitable dicarbonyl monomer solvents include chlorinated hydrocarbons such as methylene chloride, chloroform and chlorobenzene, benzene, acetone, nitrobenzene, benzonitrile, acetophenone, acetonitrile, toluene and mixtures of the above solvents such as tetrahydrofuran and benzonitrile, tetrahydrofuran and acetophenone or benzene and acetone and the like.

The amounts of the various reactants which may be employed will, of course, vary according to the type of polymer desired. However, in most instances, substantially equimolar quantities or a slight excess of diamine to dicarbonyl may be used. For interfacial polymerization reactions, suflicient proton acceptor to keep the acidic by-products neutralizde may be added, the exact amount easily determined by one skilled in the art.

Suitable emulsifying agents for interfacial polymerize. tion include anionic and nonionic compounds such as sodium lauryl sulfate, nonyl phenoxy(ethyleneoxy) ethane, the sodium orpotassium salt of any suitable condensed sulfonic acid and the like.

A proton acceptor as the term is employed herein indicates a compound which acts as an acid scavenger to neutralize HCl, formed during the reaction, and which aids to carry the reaction to completion. Suitable proton acceptors include sodium carbonate, magnesium carbonate, calcium carbonate, tertiary amines, such as triethyl amine, trimethyl amine, tripropyl amine, ethyl dimethyl amine, tributyl amine and similar compounds which react as desired.

The products of this invention are useful in a wide range of applications. In the form of fibers, filaments and films the polymers of this invention are thermally resistant as well as being resistant to acids and other types of chemical degradation. The invention is further illustrated by the following examples in which all parts and percents are by weight unless otherwise indicated. Heat resistant properties of the polymers of the invention were tested by differential thermal analysis (DTA) and thermogravimetric analysis (TGA). Inherent vihcosity values are determined at 30 C. in dimethylacetamide containing 6 percent dissolved lithium chloride, using a concentration of 0.5 g. of polymer per ml. of solvent. Fibers were characterized in general by having good strength retention above 300 C.

EXAMPLE I Preparation of 4,4'bis(p-aminophenyl)-2,2'-bithiazole The diamine used for polymerization (4,4-bis (p-aminophenyl)-2,2'-bithiazole, diamine A) was prepraed in the following manner:

. Analysis.-Calcd: C, 61.67; H, 4.02; N, 15.95. Found: C, 61.24; 61.55; H, 4.07; 4.09; N, 15.82; 15.92.

EXAMPLE II Polymers of 4,4-bis(p-aminophenyl)-2,2'-bithiazole Polymers prepared from diamine A may be illustrated by the following structures:

A. To a solution of 48.8 g. (0.2 mole) of 2-bromo-4- nitroacetophenone in 200 ml. dimethylacetamide (DMAc) was added 12.0 g. (0.01 mole) dithioxamide (rubeanic acid). After minutes, a product began to precipitate from solution. The reaction mixture was stirred overnight, then filtered. The crude product was washed in ethanol and dried to yield 30 g. of material, M.P. 324- 326 C. The procedure was repeated 5 times and the total product of the six runs combined to yield 142.1 g. of bluish-green material. The crude product was recrystallized twice from 900 ml. portions of DMAc, then recrystallized a third time from 1.5 liters DMAc to yield 121.9 g. of pure product in the form of long yellow needles, M.P. 325-327 C. Alaternately, the reaction may be run using heat and the product recrystallizes from the reaction mixture.

B. Reduction was etfected on the product prepared accordingto the method in section A above. Thus, 30 g. of 4,4-bis(pnitrophenyl)-2,2-bithiazole, 300 ml. DMAc, and 3 g. Raney nickel were placed in a bomb and pressured to 2700 p.s.i. at 30 C. The bomb was repressured to 3700 p.s.i. at 50 C.; after five hours at 120 C. the pressure was 3100 p.s.i. The bomb was cooled, vented and the contents of the bomb filtered. The filtrate was poured into 2 liters water at 50 C. and the product collected, washed in 500 ml. water, filtered off and dried 16 hours at 50 C. in vacuum oven. Thus, 23 g. or product, M.P. 275278C. was collected. The process above was repeated three times to yield 71 g. of crude diamine.

C. The crude diamine of section B above was purified A. A solution of 10.5 g. (0.03 mole) diamine A in 100 ml. DMAc containing 6 percent dissolved lithium chloride was cooled to 30 C. and 6.09 g. (0.03 mole) isophthaloyl chloride was added with stirring. After 15 minutes the solution was allowed to warm to 0 C. and after an additional 15 minutes the solution was allowed to Warm to room temperalture. The solution became so viscous that it became necessary to add another ml. solvent. After 3 hours, the solution was neutralized by addition of a slurry of 1.5 g. lithium hydroxide in 25 m1. DMAc. Two additional runs of the same size were made in the above manner. Polymer from each run was isolated by addition of water to a dilute solution of polymer. After washing and drying, a total of 40.1 g. polymer was collected having an inherent viscosity of 2.4. Fiber spun from by dissolving 23 g. of the diamine in 1 liter of water at 90 C. containing 25 ml. concentrated hydrochloric acid, heating the solution to the boil, filtering, and making the filtrate basic with 4N sodium hydroxide solution. The mixture was cooled 30 minutes, then the diamine was collected, washed with 100 ml. water, dried 16 hours at 50 C. in a vacuum oven. Two more batches of crude diamine were purified in the above manner to yield a total of 68 g. of product, which was recrystallized from 500 ml. DMAc, washed with 50 ml. methanol, dried in a vacuum oven at 50 C. for 16 hours to yield 53.5 gm. of pure diamine, M.P. 280283 C.

the polymer above and drawn at 300 C. was found to have the following physical properties:

Other pertinent fiber data were: round cross-section, high order as indicated by X-ray, a melting point of 550 C. in nitrogen for undrawn fiber according to DTA, less than 15 percent weight loss in air to 500 C. (TGA), less than 20 percent Weight loss in nitrogen to 550 C. (TGA).

B. A solution of 1.75 g. (0.005 mole) diamine A in 15 ml. DMAc containing 5 percent dissolved lithium chloride was cooled to'-30 C. and 1.02 g. (0.005 mole) terephthaloyl chloride was added. The solution was stirred 15 minutes at 30 C., and 15 minutes at 0 C. before the addition of another 5 ml. DMAc containing 6 percent dissolved lithium chloride. After 2 hours at room temperature, the mixture was neutralized with 0.25 g. lithium hydroxide slurried with 10 ml. DMAc containing 6 percent dissolved lithium hydroxide. The paste of polymer did not dissolve upon addition of 0.5 g. lithium chloride and heating of the paste to 80 C. Precipitation of the polymer in water, followed by washing and drying of the polymer gave a yield of 2.0 g. of very thermally stable material. Film showed little or no effect upon being heated to 435 C. in air; unoriented films heated to 525 C. for 3 minutes in air began to char but were still flexible.

C. A solution of 1.75 g. (0.005 mole) diamine A in 20 ml. DMAc containing 5 percent dissolved lithium chloride was cooled to 30 C. and 1.26 g. (0.005 mole) 2,6-naphthalenedicarbonyl chloride was added. The solution was stirred at -30 C. for 15 minutes, then at C. for 30 minutes. After 2 hours, the paste of polymer and solvent was neutralized with 0.24 g. lithium hydroxide slurried with 5 ml. DMAc containing 5 percent dissolved lithium chloride. The polymer was isolated by pouring the above mixture into water, washing and drying the resulting precipitate.

D. The procedure of section C was repeated using 1.39 g. of 4,4-bibenzoyl chloride instead of 2,6 naphthalenedicarbonyl chloride.

E. A solution of 1.05 g. (0.003 mole) diamine A in 9 ml. DMAc containing 6 percent dissolved lithium chloride was cooled to 30 C. and 1.03 g. (0.003 mole) 4,4'-sulfonebibenzoyl chloride was added. A very viscous, clear solution was obtained even when the solution was allowed to warm to room temperature. Film prepared from this polymer was thermally stable.

EXAMPLE III This example shows the preparation of 5,5'-di(3- aminophenyl)2,2' bis(l,3,4-oxadiazolyl), diamine B, used to prepare the polymers illustrated in Example IV.

12 A. A slurry of 5.9 g. of oxalic dihydrazide in 150 ml. water was stirred rapidly in a blender jar and 19 g. mnitrobenzoyl chloride in 25 ml. tetrahydrofuran was added. Next, 11 g. of sodium carbonate was added and the mixture was stirred rapidly for minutes. The slurry Was acidified with dilute hydrochloric acid, filtered and reduction the product washed with 700 ml. hot water. The dried material weighed 16.9 g., MP. 306-310 C. A pure material, M.P. 312-314 C. was obtained upon recrystallization from DMAc.

5 ,5 -di 3 -nitrophenyl)-2,2'-1bis(1,3,4-oxadiazolyl) B. Treatment of 9 g. of the product of section A above 5,5 -di(3-aminophenyl)-2,2-bis( 1,3,4-oxadiazoyl) C. A reduction of the dinitro compound of section B above was performed by placing 4.5 g. of dinitro compound in a solution of 15 g. stannous chloride dihydrate in 18 ml. concentrated hydrochloric acid and 30 ml. ethanol. After a 45 minute reflux period, the swollen solids were washed in ethanol, slurried with aqueous sodium hydroxide solution, washed in water and dried. The resulting crude diamine B had a M.P. of 330-333 C.; pure diamine B., M.P. 339-341 C., was obtained upon recrystallization from ethylene glycol monomethyl ether.

Analysis.-Calcd: C, 60.00; H, 3.77; N, 26.23. Found: C, 59.06, 59.27; H, 3.58, 3.74; N, 25.69, 25.76.

EXAMPLE IV Polymers prepared according to this example have the following structure:

cast into film. After the dissolved salts were removed from i the film and the film was dried, a tough gray film was obtained. The film readily increased in length when drawn at elevated temperatures and do not soften until heated to temperatures in excess of 300 C.

B. A solution of 0.48 g. (0.0015 mole) diamine B in 8 1 ml. DMAc containing -6 percent dissolved lithium chloride 1 was colled to -30 C. and 0.305 g. (0.0015 mole) terephthaloylchloride was added. The viscous solution was stirred 15 minutes at -30 C., then 15 minutes at 0 C., and finally overnight at room temperature. Next, 0.072 g. of lithium hydroxide was added to neutralize the solu- '13 14 tion, which was then cast onto a glass plate. A ob- Preparation of diamine D tained by evaporation of solvent, soaking out dissolved salts followed by air drying, was tough and clear; the A miXtlll'e f 21 g- I, 1 gof RalleY nickel, and 300 film did not soften until heated in excess of 300 C. ml. DMAc was placed in an Aminco hydrogenation ap- C. A solution of 0.64 g. (0.002 mole) diamine B in 4 paratus; the system .was pressurized with hydrogen to M Containing 5P dissolved lithium chlo- 2000 p.s.i. The temperature was raised to 120 C. and

ride was Cooled 0-505 ((1002 mole) the pressure maintained at 2600 p.s.i. for 5 hours. The 2;6-naphthalenedicarbonyl chloride was added. A paste bomb was cooled to C. vented, and the contents of of Solids was Obtained; addition of another 4 of the bomb filtered. The filtrate was poured into 1 liter of vent gave a dope which was Spread t a 10 benzene and the diamine D collected; the melting point of EXAMPLE V the crude diamine D was 276-280 C. Diamine D recrys- This example illustrates the preparation of intermedimulled from ethylene glycol monomethyl ether d' atesused to prepare the polymers of Example VI. MP. of 280-281 C.

Dlamine C 1 NET-QC 0 NH-NH-C o-o O-NHNH-C 0NH1 Raney nickel Diamine D Preparation of I a 1 EXAMPLE VI A solution of 95 g. (0.51 mole) mole 'p-nitro-benzyl Polymers prepared according to this example have the chloride in 125 ml. tetrahydrofuran was added to 29.5 g. following structure:

(0.25 mole) ovalic dihydrazide slurried in 750 ml. ice- A. A slurry of 1.60 g. (0.005 mole) diamine C in 10 water and the mixture stirred rapidly while, g. :of sodi- 0 ml. DMAc containing 5 percent dissolved lithium chlorum carbonate was added. After 15 minutes the mixture ide was cooled to 0 C. and 1.01 g. (0.005 mole) isowas made acid, filtered, and washed with hot water. The phthaloyl chloride added with stirring. The solution obdried product, I, weighed 96.0 g. (92.3 percent yield); tained was viscous but polymer shortly began to precipithe melting point was 312-3l4 C. tate. .The sluny was diluted by the addition of 13 ml. Prearafion ofn 55 DMAc containing 5 percent dissolved lithium chloride and was heated to C. The polymer was precipitated 23.4 Portion of I was heated to 240 With 3.11 BX- into water, ollected and dried,

6655 Of 2 5 hours Occasional shakinghthen B. A solution of 0.89 g. (0.0025 mole) diamine D in water and ice was added to the cooled mixture. The prod- '3 6 p DMA containing 5 percent i l d i hi not was filtered and dried to yi l gof crude P 60 chloride was cooled to 30 C. and 0.51 g. (0.0025 a recrystallization frOiIY370' DMAc gave mole) 'isophythaloyl chloride added with stirring. The

of P A p experiment using solution was allowed to warm to 0 C., then to room 20 g. of I gave 15 g. of II, M.P. 359-361 .C. Repea ru temperature, and finally was heated to 50 C. before it p ble results. was spread on a glass plate. The film'obtained. was brittle. Ahalysim calcdt' C; 50.58; H, 210; 22? Removal of water from polymer B (Example 11) by FOUIIdi C, a chemical treatment or heating above 300" C. converted Preparation of diamine C y it Pf y A E Z P S D- h b f T e oregoing eta ed escription as een given or nasti st: e 2:rsttt hztzeatitpfii: of and a aratus. The System was pressurized to 2000 psi with trons are not to be construed therefrom. The invention is drog'en and heated to 0 for a period of hours, not to be limlted to the exact details shown and described with Shaking The bomb was cooled, the contents f the since obvious modifications Wlll occur to those skilled n flask Were heated to the boil, and the slurry filtered. The the 311, and y departure fljom i f f p herein filtrate was poured into hot water, the diamine C collected 75 that conforms to the Present lnventlfm 1S Intended to be and dried (M.P. 400 C., dec.). included within the scope of the claims.

I claim: 1. An amide-heterocyclic polymer composed of regularly recurring structural units of the formula -H -Y-NH-CY-C- L N .I wherein Y and Y are selected from the group consisting of Ar and Ar-X-X-Ar wherein Ar is a divalent hydrocarbon aromatic radical oriented other than ortho, X is a divalent 5 or 6 ring member heterocyclic radical con- 0 ima es}.

16 wherein R is a divalent aromatic radical oriented other than ortho selected from the group consisting of 4. An amide-heterocyclic polymer composed of regu larly recurring structural units of the formula wherein R is a divalent aromatic radical oriented other than rortho selected from the group consisting of 5. An amide heterocyclic polymer composed of regularly recurring structural units of the formula wherein Y and Y are selected from the group consisting of Ar and Ar-X-X-Ar wherein Ar. is a divalent hy- 6. An amide-heterocyclic polymer composed of regularly recurring structural units of the formula drocarbon aromatic radical oriented other than ortho and containing from 6 to 15 carbon atoms, X is a divalent 7. An amide-heterocyclic polymer composed of regularly recurring structural units of the formula 5 or 6 ring member heterocyclic radical containing from 1 to 3 hetero elements selected from As, N, O, P, S, and 45 Se wherein all, occurrences of X in the structural unit must be the same, wherein at least one Ar-X-X-Ar radical must be present in each recurring structural unit,

and wherein there is at least one plane of symmetry in each repeating unit.

8. The polymer of claim 1 in the form of a fiber.

9. The polymer of claim 1 in the form of a film.

10. An amide-heterocyclic polymer intermediate polymer composed of regularly recurring structural units of the formula 11. An amide-heterocyclic polymer composed of regularly recurring structural units of the formula N O O lNHc C H C sHr sOFQtl 3. An amide-heterocyclic polymer composed of regu- 60 larly recurring structural units of the formula References Cited UNITED STATES PATENTS 8/1962 Stephens 260-78 4/1965 Frost et a1. "260 -78 WILLIAM H. SHORT, Primary Examiner. H. D. ANDERSON, Assistant Examiner. 

1. AN AMIDE-HETEROCYCLIC POLYMER COMPOSED OF REGULARLY RECURRING STRUCTURAL UNITS OF THE FORMULA 